Honeycomb panel laminates each having a honeycomb material as a core material and two face materials between which the honeycomb material is sandwiched are used in the fields of aircrafts, railroad vehicles, and building materials. In these fields, the honeycomb panel laminates have generally been used as weight-saving and strengthening members, and have mostly been used in a hollow state with no filling in a honeycomb cell space.
On the other hand, sound absorbing and heat insulating laminates each having a honeycomb material and two faces, each made of a metal or fiber-reinforced plastic having sound absorbing and heat insulating capabilities (FRP, CFRP, KFRP), between which the honeycomb material is interposed have comes to be widely used in ships, aircrafts, etc. (Patent Literature 1) and, furthermore, improved laminates have come each of which has a better sound insulation characteristic by having a sound absorbing layer obtained by filling honeycomb cell spaces with a member having a sound absorption characteristic (Patent Literature 2).